Heretofore there have been many different types of safety means provided for press brakes. A number of these systems involve complicated electronic control circuits usually controlling both electrical and pneumatic control apparatus therein, examples of which structures are shown in U.S. Pat. Nos. 3,534,844 and 3,554,067. One relatively uncomplicated pneumatic control system for positioning a guard in operative position in a pressing apparatus and which insures that the guard is in guarding position before press closing action occurs, is shown in U.S. Pat. No. 2,888,123 while another relatively simple safety guard apparatus and control means is shown in U.S. Pat. No. 3,213,992. While these previously known types of press brake guards and other varieties of the same have been proposed heretofore, all of such controls are relatively complex, difficult to install on existing machinery, or they may not be absolutely positive in acting under all operative conditions.
The general object of the present invention is to provide relatively uncomplicated fail safe guard control means for use with a mechanically driven press brake.
Another object of the invention is to provide a press brake guard apparatus and control system especially adapted for use with mechanically operated and driven press brakes and to provide a positive acting mechanical safety control in the press brake drive means.
Yet another object of the invention is to provide an air pressure control system for a guard used with a press brake; to stop brake operation if an obstruction is present in the ram path; and to insure that the press brake cannot be operated when air pressure supply thereto terminates.
Yet other objects of the invention are to provide apparatus of the type described and wherein control means are present for automatically setting the guard in a safe position if the machine or brake is recycled without removing one's foot from the foot treadle; to use a lightweight supplemental bar on the guard to signal contact with an obstruction as the guard moves downwardly; another object is to terminate press brake action rapidly should any obstruction be contacted by the guard member when moving down into operative guard position; to use substantially commercial components in an air pressure control system for a press brake guard; and, to provide a press brake guard applicable to existing machinery with a minimum of changes thereto.
The foregoing and other objects and advantages of the invention will be made more apparent as the specification proceeds.